The invention relates to a vehicle brake booster tie rod. The invention also relates to a booster using such a tie rod.
In a motor vehicle, the brake booster is generally positioned in the forward compartment of the vehicle, which is often the engine compartment. As depicted in FIG. 1, the booster casing comprises a front wall 50 and a rear wall 51. Inside the casing is the skirt 52 which, as is known in the art, allows forces F transmitted by a control rod 1 and a piston 10 to be passed on to a push rod which imparts the forces to the master cylinder 6.
It is known practice in the state of the art for the booster to be secured to the bulkhead dividing the forward compartment of the vehicle from the driver's compartment.
According to the method of attachment of FIG. 1, the securing means comprise rods or tie rods that pass right through the booster casing.
This method of attachment has the advantage that the tie rods such as 2 can comprise means for setting the distance between the front 50 and rear 51 walls of the booster and for thus axially stiffening the booster.
However, these tie rods pass through the front chamber 53 of the booster, in which chamber a vacuum is to be created so that the booster can, as is its purpose, afford the desired brake boost. There must therefore not be any leaks around these tie rods in the regions where they pass, on the one hand, through the front wall 50 of the booster and, on the other hand, through the skirt 52.
Furthermore, at its two ends, each tie rod has threaded parts 20 and 21 onto which nuts can be screwed. The threaded part 20 allows the booster to be secured to a bulkhead of the engine compartment and the threaded part 21 allows the master cylinder 6 to be secured to the booster.
As can be seen in FIG. 1, each tie rod is often crimped into the rear wall of the booster, and this may cause deformations at the time of crimping. In addition, the tightening of the securing nuts onto the threaded parts creates stress in the tie rods.
It is an object of the invention to solve these disadvantages.